Service exposure, including service publication and discovery, plays an important role in next generation service delivery. Various solutions to service exposure have been proposed in the last decade, by both academia and industry. Most of these solutions are targeting specific developer groups, and generally use centralized solutions, such as UDDI. However, the reality is that the number of services is increasing drastically with their diverse users. How to facilitate service discovery and publication processes, improve service discovery, selection efficiency and quality, and enhance system scalability and interoperability are some challenges faced by the centralized solutions. In this paper, we propose an alternative model of scalable P2P-based service publication and discovery. This model enables converged service information sharing among disparate service platforms and entities, while respecting their intrinsic heterogeneities. Moreover, the efficiency and quality of service discovery are improved by introducing a triplex-layer based architecture for the organizations of nodes and resources, as well as for the message routing. The performance of the model and architecture is evident by theoretical analysis and simulation results.